This invention relates to cathode ray tube electron gun structures and more particularly to improved means for supporting the cathodes utilized therein.
In present day television equipment utilizing thermionic electron emission devices, the time required for cathode warm-up has long been recognized as an important factor in determining the span of time between equipment turn-on and operational response. The substantially instantaneous activation of solid state circuitry has made the warm-up time required of the cathode ray tube (CRT) thermionic cathode means a major deterrent to the achieving of a rapid operational state. Such CRT cathodes are conventionally cylindrical sleeves having closed ends whereupon electron emissive material is terminally disposed. Heating elements encompassed within the sleeves provide the thermal energy necessary to achieve electron emission.
These cathode elements have been supported within the electron gun structure in several ways, i.e., by crimping or otherwise affixing the sleeve within an apertured supporting ceramic, or by several adaptations of metallic cylindrical members or eyelets wherein the cathode sleeve is substantially encompassed and positionally affixed. Such supportive means have all evidenced appreciable conductive contact with the cathode sleeve thereby producing undesirable heat sink characteristics, which relate directly to the length of the pre-operational time span.